Did you try to use Search for "Confixx" word on Parallels Plesk Panel for Linux/Unix and child forums? There are a lot of threads about migration from Confixx to Plesk. Now we have migration agent only for 9.x version.

There are a lot of difference between Plesk 9.x and Plesk 10.x therefore agent for 9.x will not work correctly for 10.x in any case. I think that now you can use only one method - use latest available version of Confixx migration agent and try to migrate Confix to Plesk 9.x After successful migration you can perform upgrade to 10.x version.